sorry, but i'm getting trouble in the first level.. i have 36 seconds for the gold.. first wave I can do in around 9, but then there are big pauses between second wave, and then between third wave, the enemies simply don't spawn fast enough..?
You have to get stronger and invite a strong friend to help you.
In my case, i use exactly 36 secs when i was about level 20. Then again, the gold chest in level1 is useless if you are level 20. ^-^~